[PATCH V2 14/35] selftest/powerpc/pmu: Add interface test for bhrb disable field for non-branch samples

[Athira Rajeev]

From: Kajol Jain <kjain at linux.ibm.com>

The testcase uses "instructions" event to generate the
samples and fetch Monitor Mode Control Register A (MMCRA)
when overflow. Branch History Rolling Buffer(bhrb) disable bit
is part of MMCRA which need to be verified by perf interface.
Incase sample is not of branch type, bhrb disable bit is explicitly
set to 1. Testcase checks if the bhrb disable bit is set of MMCRA
register via perf interface for ISA v3.1 platform

Signed-off-by: Kajol Jain <kjain at linux.ibm.com>
---
 .../powerpc/pmu/sampling_tests/Makefile       |  2 +-
 .../mmcra_bhrb_disable_no_branch_test.c       | 64 +++++++++++++++++++
 2 files changed, 65 insertions(+), 1 deletion(-)
 create mode 100644 tools/testing/selftests/powerpc/pmu/sampling_tests/mmcra_bhrb_disable_no_branch_test.c

diff --git a/tools/testing/selftests/powerpc/pmu/sampling_tests/Makefile b/tools/testing/selftests/powerpc/pmu/sampling_tests/Makefile
index f966d3359c6b..9e67351fb252 100644
--- a/tools/testing/selftests/powerpc/pmu/sampling_tests/Makefile
+++ b/tools/testing/selftests/powerpc/pmu/sampling_tests/Makefile
@@ -7,7 +7,7 @@ TEST_GEN_PROGS := mmcr0_exceptionbits_test mmcr0_cc56run_test mmcr0_pmccext_test
 		   mmcr3_src_test mmcra_thresh_marked_sample_test mmcra_thresh_cmp_test \
 		   mmcra_bhrb_ind_call_test mmcra_bhrb_any_test mmcra_bhrb_cond_test \
 		   mmcra_bhrb_disable_test bhrb_no_crash_wo_pmu_test intr_regs_no_crash_wo_pmu_test \
-		   bhrb_filter_map_test mmcr1_sel_unit_cache_test
+		   bhrb_filter_map_test mmcr1_sel_unit_cache_test mmcra_bhrb_disable_no_branch_test
 
 top_srcdir = ../../../../../..
 include ../../../lib.mk
diff --git a/tools/testing/selftests/powerpc/pmu/sampling_tests/mmcra_bhrb_disable_no_branch_test.c b/tools/testing/selftests/powerpc/pmu/sampling_tests/mmcra_bhrb_disable_no_branch_test.c
new file mode 100644
index 000000000000..488c865387e4
--- /dev/null
+++ b/tools/testing/selftests/powerpc/pmu/sampling_tests/mmcra_bhrb_disable_no_branch_test.c
@@ -0,0 +1,64 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright 2022, Kajol Jain, IBM Corp.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "../event.h"
+#include "misc.h"
+#include "utils.h"
+
+extern void thirty_two_instruction_loop(int loops);
+
+/* Instructions */
+#define EventCode 0x500fa
+
+/*
+ * A perf sampling test for mmcra
+ * field: bhrb_disable.
+ */
+static int mmcra_bhrb_disable_no_branch_test(void)
+{
+	struct event event;
+	u64 *intr_regs;
+
+	/*
+	 * Check for platform support for the test.
+	 * This test is only aplicable on power10
+	 */
+	SKIP_IF(check_pvr_for_sampling_tests());
+	SKIP_IF(!have_hwcap2(PPC_FEATURE2_ARCH_3_1));
+
+	 /* Init the event for the sampling test */
+	event_init_sampling(&event, EventCode);
+	event.attr.sample_regs_intr = platform_extended_mask;
+	event.attr.exclude_kernel = 1;
+
+	FAIL_IF(event_open(&event));
+	event.mmap_buffer = event_sample_buf_mmap(event.fd, 1);
+
+	FAIL_IF(event_enable(&event));
+
+	/* workload to make the event overflow */
+	thirty_two_instruction_loop(10000);
+
+	FAIL_IF(event_disable(&event));
+
+	intr_regs = get_intr_regs(&event, event.mmap_buffer);
+
+	/* Check for intr_regs */
+	FAIL_IF(!intr_regs);
+
+	/* Verify that bhrb_disable bit is set in MMCRA for non-branch samples */
+	FAIL_IF(!get_mmcra_bhrb_disable(get_reg_value(intr_regs, "MMCRA"), 5));
+
+	event_close(&event);
+	return 0;
+}
+
+int main(void)
+{
+	return test_harness(mmcra_bhrb_disable_no_branch_test, "mmcra_bhrb_disable_no_branch_test");
+}
-- 
2.35.1